952 Tie CLRIGES: 
lapping wing-coverts were shewn many years ago by Sundevall? to 
have a taxonomic value, and the later researches of Mr. Goodchild 
(Proc. Zool. Soc. 1886, pp. 184-203) have carried the matter further. 
The latter distinguishes seven different types of arrangement in the 
wing-coverts : 
1. All the Upper feathers overlap proximally: only 3 or 4 
transverse rows owing to the absence of the Lesser coverts, which 
are represented by enlarged marginals—Cypselidx and Trochali. 
2. Lesser coverts absent, marginals enlarged and overlapping 
proximally : Middle Upper coverts reduced to one row and over- 
lapping distally—Oscines. 
3. One row af Middle and 5 or 6 rows of Lesser Upper coverts, 
all overlapping proximally —Cuculidx, Musophagidx, Coracias, Indi- 
cator and Caprimulgus. 
4. One row of Middle and from 2 to 4 rows of Lesser coverts 
overlapping distally—Picidx, Rhamphastidx, Alcedinide and Chasmo- 
rhynchus. 
5. The Middle row and from 3 to 6 Lesser rows overlap distally, 
except the feathers toward the elbow, which overlap proximally— 
—the meeting-place of these two differently-disposed groups being 
generally very conspicuous. This is the most common and possibly 
the most generalized type, from which all the rest may be derived, 
and occurs in Falconidx, Psittaci, Striges, Herod, Phalacrocoraz, 
Anseres, Meleagris and many Gulline, Gouru, Rallidx, Limicolx, Ciconia, 
Platalea and Ibis. 
6. The whole row of Middle coverts overlaps proximally ; numer- 
ous rows of Lesser, but those which overlap distally are restricted 
to a patch on the middle of the Upper surface—Columba, Ptero- 
clidx, Laridx, Sula, Serpentarius. 
7. Numerous rows of Upper coverts all overlapping proximally 
—Mycteria, Leptoptilus, Fregata, Plotus, Diomedea, Ossifraga, Puffinus, 
Cathaurtide. 
Considering that all the birds of this last type are remarkable 
for the length of their wing-bones, and consequently the great 
number of remiges, as well as the fact that other Ciconizw, Tubinares 
and Steganopodes belong to a different type, it seems reasonable to 
think that the character of this group is the result of specialization, 
and has been independently acquired, without indicating any rela- 
tionship. On the other hand, the agreement between Cypselidx 
and T'rochili, Columbe and ~Pleroclidx, both indicating a reference to 
Limicolz, and the similarity between Cathartidxe and Steganopodes as 
well as Pelargi are at least suggestive of taxonomic value ; but for 
further information Mr. Goodchild’s treatise, whence some figures 
are here introduced, should be consulted. 
1 Kk. Vetensk.-Ak. Handi. 1843, pp. 803-384. A translation of this memoir by 
Dallas appeared in 7he bis, 1886, pp. 389-457, pls. x. xi. 
